4 Billion Years On

Greenhouse Gases

CO₂, methane and nitrous oxide against pre-industrial levels, and the warming they drive…

Atmospheric concentrations of carbon dioxide, methane and nitrous oxide, each tracked against pre-industrial baselines, alongside global temperature, Arctic sea ice and ocean surface warming. Long-term histories show how the gases have risen and how that turns into measurable change - land warming faster than sea, ice retreating, and the Paris Agreement limits drawing closer.

Latest data Sep 2026

Current Readings

CO₂
426.1ppm
+52% vs pre-industrial
Sep 2026
CH₄
1935ppb
+168% vs pre-industrial
Jun 2026
N₂O
339.9ppb
+26% vs pre-industrial
Jun 2026
Global Temp
+1.22°C
Land + ocean vs 1961‑90
Sep 2026
Ocean Temp
+0.97°C
Sea surface vs 1961‑90
Sep 2026
Arctic Sea Ice
4.8M km²
−0.8 M km² vs average
Sep 2026

Data: NOAA GML (CO₂, CH₄, N₂O — Mauna Loa & global network) · NOAA NCEI (temperature anomalies vs 1961–1990) · NSIDC (Arctic sea ice)

4byo Climate Helix Heatwave Days

Monthly Indicators

CO₂, Heat & OceansCO₂, Temperature & Ocean Anomalies

Monthly, last 5 years · vs 1961-1990 (NOAA)

CO₂
426.1ppm
Sep 2026
Land + Ocean
+1.22°C
Sep 2026
Sea Surface
+0.97°C
Sep 2026
CO₂ (ppm)Land + Ocean (°C)Ocean Anomaly (°C)Paris +1.5°Cthick = 12-month avg

CO₂ seasonal trend (NOAA GML, Mauna Loa) · temperature and ocean anomalies vs 1961–1990 baseline (NOAA NCEI)

Annual History

CO₂ & TemperatureCO₂ & Global Temperature

CO₂ vs land + ocean temperature

CO₂ safe boundary: 350 ppmParis +1.5°C

As CO₂ rises, global temperatures track upward in near-lockstep - a correlation that holds across every timescale. Sources: NOAA GML (CO₂) · NOAA NCEI (land + ocean temperature, vs 1961-1990).

Rise of Each GasAll Greenhouse Gases – Percentage Rise

% above pre-industrial levels

Pre-industrial levelCO₂ safe boundary (350 ppm ≈ 25%)

All three gases as percentage increase above pre-industrial levels, showing how each amplifies the others' warming effect. Sources: NOAA Global Monitoring Laboratory via global-warming.org.

Greenhouse Gases

CO₂ ConcentrationAtmospheric CO₂ Concentration

Yearly average CO₂ concentration (ppm)

Pre-industrial: 280 ppm

* 2026 is year-to-date (Jan-Sep only, partial year)

CO₂ is the primary driver of climate change, responsible for about two-thirds of total warming. Continuous measurements from Mauna Loa date back to 1958. Source: NOAA Global Monitoring Laboratory (Mauna Loa Observatory).

Methane (CH₄)Atmospheric Methane Concentration

Yearly average methane concentration (ppb)

Pre-industrial: 722 ppb

* 2026 is year-to-date (Jan-Jun only, partial year)

Methane is over 80× more potent than CO₂ over 20 years. Major sources include agriculture, fossil fuel extraction, and wetlands. Source: NOAA GML via global-warming.org.

Nitrous Oxide (N₂O)Atmospheric Nitrous Oxide Concentration

Yearly average N₂O concentration (ppb)

Pre-industrial: 270 ppb

* 2026 is year-to-date (Jan-Jun only, partial year)

N₂O has nearly 300× the warming potential of CO₂ over 100 years and also depletes the ozone layer. The primary source is agricultural fertiliser. Source: NOAA GML via global-warming.org.

FAQs

FAQs

What does the greenhouse gases page show?

Live atmospheric concentrations of the three main long-lived greenhouse gases - carbon dioxide (CO₂), methane (CH₄) and nitrous oxide (N₂O) - each since modern measurements began, how far each has risen above its pre-industrial level, and how CO₂ has tracked global temperature. Current values and the last five years month by month are in the panels above.

Which greenhouse gases matter most for climate change?

Carbon dioxide is the largest single contributor to human-caused warming and the longest-lived in the atmosphere. Methane has a much shorter lifetime but a far stronger warming effect per molecule. Nitrous oxide has a long lifetime and is the third-largest contributor. Fluorinated gases (HFCs, PFCs, SF₆) and water-vapour feedback also play a role; the major three are tracked on this page.

Where does the greenhouse gas data come from?

Modern atmospheric measurements: NOAA Global Monitoring Laboratory, including the Mauna Loa Observatory and the global air-sampling network; global temperature from NOAA NCEI. Live monthly updates are sourced via the global-warming.org public API, which mirrors the NOAA feeds.

How are the numbers expressed?

CO₂ is reported in parts per million (ppm). Methane and nitrous oxide are reported in parts per billion (ppb). Trend lines remove the seasonal cycle to show the underlying year-on-year change. Pre-industrial levels (around 1750) are noted on each chart for reference.

How often is this page updated?

Monthly atmospheric measurements refresh each month, typically within a few weeks of the measurement date.

Is this page suitable for students studying climate change?

Yes. The greenhouse gases page covers material directly relevant to UK GCSE and A-level Geography (carbon cycle, climate change causes), IB Environmental Systems and Societies (Topic 3: Climate and energy) and AP Environmental Science (Unit 7: Atmospheric pollution, Unit 9: Global change). The live concentration data and the rise above pre-industrial levels are particularly useful for illustrating the scale and pace of change since industrialisation. Citation formats for academic work are available at /climate-education.

What is the difference between CO₂ concentration and CO₂ emissions?

CO₂ concentration (measured in parts per million, ppm) is the amount of carbon dioxide currently in the atmosphere - it is what this page tracks. CO₂ emissions are the annual flow of new carbon dioxide released by human activity. Emissions are like water flowing into a bath; concentration is the level of water in the bath. Because CO₂ persists in the atmosphere for centuries, concentration continues to rise even as emission growth slows. Country-level emissions data is available on the CO₂ Emissions page at /emissions.